All forms of vascular reconstruction such as angioplasty and vein bypass procedures effect a response to injury that ultimately leads to smooth muscle cell (SMC) proliferation and, subsequently, deposition of profuse amounts of extracellular matrix (Clowes, A. W.; Reidy, M. A. J. Vasc. Surg 1991, 13, 885). These events are also central processes in the pathogenesis of atherosclerosis (Raines E. W.; Ross R. Br. Heart J. 1993, 69 (Supplement), S 30) as well as transplant arteriosclerosis (Isik, F. F.; McDonald, T. O.; Ferguson, M.; Yamanaka, E.; Gordon Am. J. Pathol. 1992, 141, 1139). In the case of restenosis following angioplasty, clinically relevant solutions for controlling SMC proliferation through pharmacological intervention have remained elusive to date (Herrman, J. P. R.; Hermarts, W. R. M.; Vos, J.; Serruys P. W. Drugs 1993, 4, 18 and 249). Any successful approach to selective SMC proliferation inhibition must not interfere with endothelial cell repair or the normal proliferation and function of other cells (Weissberg, P. L.; Grainger, D. J.; Shanahan C. M.; Metcalfe, J. C. Cardiovascular Res. 1993, 27, 1191). Indeed, an important therapeutic consideration is to promote reendotheliaztion of the injured area concurrent with SMC proliferation inhibition (Casscells, W. Circulation 1992, 86, 722; Reidy, M. A.; Lidner, V. in Endothelial Cell Dysfunctions, Simionescu, N. and Simionescu M., Ed. Plenum Press, N.Y. N.Y., (1992), 31).
The glycosaminoglycans heparin and heparin sulfate are endogenous inhibitors of SMC proliferation, yet are able to promote endothelial cell growth (Castellot, J. J. Jr.; Wright, T. C.; Karnovsky, M. J. Seminars in Thrombosis and Hemostasis 1987, 13, 489; Wight, T. N. Arteriosclerosis 1989, 9, 1). However, the full clinical benefits of heparin, heparin fragments, chemically modified heparin, low molecular weight heparins, and other heparin mimicking anionic polysaccharides may be compromised due to other pharmacological liabilites (excessive bleeding arising from anticoagulation effects, in particular) coupled with heterogeneity of the various preparations (Borman, S. Chemical and Engineering News, 1993, June 28, 27; Schmid, K. M.; Preisack, M.; Voelker, W.; Sujatta M.; Karsch, K. R. Seminars in Thrombosis and Hemostasis 1993, 19 (Suppl. 1), 155; Amann, F. W.; Neuenschwander, C.; Meyer, B. Seminars in Thrombosis and Hemostasis 1993, 19 (Suppl. 1 ), 160; Radhakrishnamurthy, B.; Sharma, C.; Bhandaru, R. R.; Berenson, G. S.; Stanzani, L.; Mastacchi, R. Atherosclerosis, 1986 60, 141; Maffrand, J. P.; Hervert, M. M.; Bernat, A.; Defreyn, G.; Delevassee, D.; Savi, P.; Pinot, J. J.; Sampol, J. Seminars in Thrombosis and Hernostasis, 1991, 17 (Suppl. 2), 186). Since the anticoagulant effects of many of these agents are independent of SMC antiproliferative activity, it would be expected that polyanionic agents which are more homogenous in composition and of more defined molecular structure would exhibit a more desirable profile with fewer side effects associated with the aforementioned anionic polysaccharides.